1. Division of Dermatology; McGill University Health Centre; Montreal Quebec Canada
2. Section of Dermatopathology; Department of Pathology; The University of Texas MD Anderson Cancer Center; Houston Texas
3. Division of Clinical Epidemiology; McGill University Health Centre; Montreal Quebec Canada
4. Cancer Epidemiology and Surveillance Branch; Texas Cancer Registry; Department of State Health Services; Austin Texas
5. Department of Dermatology; The University of Texas MD Anderson Cancer Center; Houston Texas.